JARS v64n3 - Comments on the New Edition of the International Code of Nomenclature for Cultivated Plants

Comments on the New Edition of the International Code of Nomenclature for Cultivated Plants
Donald H. Voss
Vienna, Virginia

The eighth edition of the International Code of Nomenclature for Cultivated Plants (ICNCP) includes not only new rules and recommendations but also new appendices containing helpful information and guidance. The book is longer than the previous edition (184 pages, compared with 123 pages) and larger (19 x 25.5 cm, compared with 16.5 x 24 cm). The size of type fonts has been increased, making text more readable, and the price has been decreased from 55 euros to 20 euros for non-members of the International Society for Horticultural Science, making the book more affordable. Anyone seriously interested in naming cultivars or in the correct use of cultivar names should have this volume.

The following discussion is selective, not comprehensive - notably, it omits mention of important additions relating to the category "grex," used exclusively in orchid nomenclature. Many of the additions in this edition aim at clarifying concepts and rules and, importantly, providing explanations and examples to help users in applying the Code. In the latter regard, seven new appendices have been added, five of which are of particular interest here:

• Appendix IV lists libraries with significant collections of nursery catalogs.
• Appendix VII is a 3–½ page mini-tutorial on the Botanical Code rules governing Latin names of plants. This is important information for those naming cultivars, because the first element of a cultivar name is the genus name, often the Latin botanical name.

• Appendix VIII is a "Nomenclatural Filter" - a series of questions to be answered YES/NO to check whether a cultivar epithet is (a) established or (b) accepted. Each question is keyed to one or more articles of the ICNCP. Separate series of questions are provided for cultivar, Group, grex (orchid), or graftchimaera epithets.

• Appendix IX provides introductory guidance for those naming new cultivars. It discusses considerations for determining if one really has a new cultivar, for naming a cultivar, and what to do with the name. Although registration of a new cultivar name with an International Cultivar Registration Authority is not a condition for establishment of a name (Art. 27.1), it is for many reasons highly desirable. The Appendix does not, however, state the matter in these terms; it simply states "...register it with the appropriate ICRA."

• Appendix X is particularly important for those selling plants, preparing nursery catalogs and labels, or publishing information about cultivated plants. Dealing with trade designations and peripherally with trademarks, this is arguably the most useful of the appendices. For too long, there has been confusion about the relation of trade designations and cultivar epithets and about the proper way to present these names in publications and on plant labels. Examples of acceptable formats for presentation are provided.

Following the appendices, a 23-page glossary provides definitions for terminology used throughout the ICNCP, and a 17-page, 2-column subject index greatly facilitates navigating the document.

New Wrinkles in the ICNCP

In the Preface, the authors of the new edition mention that one of their objectives is to simplify language in the ICNCP to make it more accessible to non-taxonomists. A step in this direction was replacement of the phrase "distinguishable group of plants" with the word "taxon," defined as "a group into which a number of similar entities may be classified."

The following notes omit a number of additions to the ICNCP that this author judges to be of minuscule interest. The author asks for the reader's forbearance anent an attempt to introduce a note of levity. Upon learning that cultivar epithets may now contain two exclamation marks provided they are not adjacent, one is tempted to contemplate the intellectual struggle that led to limiting the number to two. A famed college cheer might be appropriate as the epithet for a spectacular cultivar; but why should the epithet be limited to "SISS! BOOM!" or "BOOM! BAH!" instead of the full "SISS! BOOM! BAH!"?

A cultivar name may comprise minimally (1) the genus name (either the Latin name or an unambiguous common name) and (2) the cultivar epithet. It is now recommended that, when known, the Latin specific epithet or unambiguous common name for the species be included in the first element. The intent is to provide information of greater value to the user of the name. (Rec. 21A.1.) Given the state of confusion in common names, especially below the rank of genus, using the Latin botanical name as the first element of a cultivar name appears to be the sounder choice.

The definition of cultivar has been expanded to include plants resulting from a change in ploidy level. (Art. 2.17)

To become established, a cultivar name must be published and otherwise conform to the rules of the ICNCP. In general, publication may not be effected by means of electronic media. An exception has now been made for names in trade catalogues published in electronic media; such names may be established if two copies of the catalogue are printed off and deposited with a designated library. (Arts. 25.1, 27.1, and Rec. 25B.2)

With respect to date of publication, it is now recommended that, where a printed trade catalogue or other publication comprises sheets that are not permanently bound, each sheet is to be clearly dated at least as to the year. (Rec. 26 A.1.)

Group Names

The formal category known as "Group" has caused confusion in the world of horticulture. According to the Glossary, the Group denotes "an assemblage of cultivars, individual plants, or assemblages of plants on the basis of defined similarity." Art. 3.1 defines the basis more precisely, namely as "defined character-based similarity." The new Art. 3.2 states that the criteria may vary "according to the required purposes of particular users" - subject, of course, to the requirement for similarity that is the basis for establishment of the Group.

An example makes clear that the Group category is not meant for use with an assemblage of plants identified merely by their origin or originator and lacking character-based similarity. (Art. 3, Ex. 14) Thus while Ghent, Knap Hill, Glenn Dale, and Indian azaleas may be considered to be informal groups, they have no status as Groups under the ICNCP.

As in the two previous editions, provision is made for Group recognition of plants that have distinctive horticultural value although the botanical taxon to which they belong has been sunk into another. In Rhododendron , for example, the plants in R. mishmiense , now placed in synonymy under R. boothii , may be known as R. boothii Mishmiense Group. (Art. 3.3) It is now recommended that when a new Group name is published based on a Latin botanical epithet, the full name of the source taxon should be cited. For example, in publishing Mishmiense Group in R. boothii , reference should be made to R. mishmiense Hutch. & Kingdon-Ward. (Art. 27E.1.)
Most of the rules applying to formation of cultivar epithets are also applicable to formation of Group names. Use of the word "group" is, however, proscribed for use in cultivar epithets. It was, therefore, necessary to provide an exception permitting the use of the word "group" as the first or last word in a Group epithet. (Art. 22.6)

Other Matters

In the rules governing the presentation of cultivar names, a Note that will please many authors, editors, and readers has been added. When the first element of a cultivar name (the genus name, for example) is perfectly clear from the context, the cultivar epithet may appear alone. (Art. 21, Note 1) Paralleling this provision, a Group name may now be used alone when the genus name is clear from the context. (Art. 22, Note 1)

A new article warns of the danger of a trademark's becoming generic (i.e., available for common use) unless it is accompanied by an accepted name for the cultivar. (Art. 8, Note 2, App. X (h))

Although a name accepted by a statutory registration authority may not be rejected, an International Cultivar Registration Authority need not register it. (Div. IV. 4.) If an accepted cultivar name is replaced by a name designated by a statutory plant registration authority, the earlier name is treated as a synonym of the new name and may become a trade designation for use in marketing the cultivar. (Art. 11.2 and Note 1)

The Code now recommends that the working name for a new cultivar (i.e., a name used in developing and testing a new cultivar) should not be adopted for another cultivar. (Rec. 21C.1.) One way to prevent confusing working names with cultivar epithets or rendering a good name unavailable for later use is to formulate working names or codes in a manner grossly contrary to the rules for formation of cultivar epithets.

The seventh (2004) and eighth (2009) editions of the ICNCP have moved toward becoming protectors of morality. The sixth edition (1995) provided that a cultivar epithet or Group epithet "must not be rejected" merely for being - among other things - insulting. (Art. 27.3) In 2004 a breach appeared in this wall: Art. 27.3 of the 1995 edition was deleted, and a recommendation was added to the effect that a cultivar name with an epithet that might cause offense should not be published. (Rec. 19H.1.) In 2009 the matter came to be treated in an article, but with a bureaucratic process interposed. As the matter now stands, someone who thinks that an epithet "might cause undue offense" may apply for a ruling by the IUBS International Commission for the Nomenclature of Cultivated Plants. (Art. 31.8) One can only wonder at the criteria to be considered in interpreting "if thought," "might cause," and "undue offense."

Additional instructions have been added concerning the use and maintenance of images as standards or otherwise included in standard portfolios. (Div. V, Notes 4-7)


Trehane, P., Brickell, C.D., Baum, B.R., Hetterscheid, W.L.A., Leslie, A.C., McNeill, J., Spongberg, S.A., Vrugtman, F. (eds.). 1995. International Code of Nomenclature for Cultivated Plants - 1995 (ICNCP). Regnum Vegetabile 133. Wimborne, UK: Quarterjack Press. 175 pp.
Brickell, C.D., Baum, B.R., Hetterscheid, W.L.A., Leslie, A.C., McNeil, J., Trehane, P., Vrugtman, F., Wiersema, J.H. (eds.). 2004. International Code of Nomenclature for Cultivated Plants . 7th Ed. Regnum Vegetabile 144. Gent-Oostaker, Belgium: Drukkerij Geers. 123 pp.
Brickell, C.D., Alexander, C., David, J.C., Hetterscheid, W.L.A., Leslie, A.C., Malecot, V., Xiaobai Jin, Cubey, J.J. (eds.). 2009. International Code of Nomenclature for Cultivated Plants . 8th Ed. Regnum Vegetabile 151. Gent-Oostaker, Belgium: Drukkerij Geers. 184pp.

Don Voss
Don Voss is a member of the Potomac Valley Chapter and a 2010 ARS Gold Medal recipient.